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This study aimed to determine a critical C-reactive protein (CRP) threshold for sufficient intestinal iron absorption using standardized tests.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Subjects\/Methods<\/jats:title>\n            <jats:p>This retrospective, cross-sectional study was conducted in a geriatric acute care unit. Serum iron and CRP levels were measured before breakfast and two- and four-hours after ingestion of two iron capsules. Intestinal iron absorption was calculated by subtracting baseline values from those obtained after the test, with an increase of 100 ug\/dl indicating sufficient absorption. Patients were categorized into six CRP groups: \u22640.50, 0.51\u20132.50, 2.51\u20135.0, 5.1\u20137.50, 7.51\u201310.0, and \u226510.1\u2009mg\/dl.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results<\/jats:title>\n            <jats:p>The study included 59 participants (73% females, age range 71\u201399). Iron absorption was highest in groups with lower CRP levels \u22640.50 to 2.5\u2009mg\/dl) and declined significantly as CRP increased, particularly beyond 5\u2009mg\/dl. The most significant decline was noted in patients with CRP\u2009\u2265\u200910.1\u2009mg\/dl. A negative correlation between inflammation, as measured by CRP, and iron absorption was found. As CRP levels escalate, there is a significant reduction in the increase of serum iron levels after 2\u2009h. A regression analysis showed that only elevated CRP levels significantly reduced serum iron increments post-iron supplementation (<jats:italic>P<\/jats:italic>\u2009=\u20090.004), while other factors such as age, sex, body mass index, frailty, weight loss, hemoglobin and nutritional status had no significant impact.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusion<\/jats:title>\n            <jats:p>A CRP level above 5\u2009mg\/dl is indicative of significantly impaired intestinal iron absorption in older patients, underscoring the critical influence of inflammation on iron metabolism.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1038\/s41430-025-01604-2","type":"journal-article","created":{"date-parts":[[2025,3,27]],"date-time":"2025-03-27T04:55:57Z","timestamp":1743051357000},"page":"774-779","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Impact of inflammatory status on intestinal iron absorption in older hospitalized patients"],"prefix":"10.1038","volume":"79","author":[{"given":"Baigang","family":"Wang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7265-0163","authenticated-orcid":false,"given":"Rainer","family":"Wirth","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elena","family":"Bergmann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lukas","family":"Funk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3771-1394","authenticated-orcid":false,"given":"Chantal","family":"Giehl","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabel","family":"Levermann","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0143-2556","authenticated-orcid":false,"given":"Gero","family":"Lueg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom","family":"Roloff","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Schnepper","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kiril","family":"Stoev","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rawi","family":"Zubi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nina Rosa","family":"Neuendorff","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5486-0765","authenticated-orcid":false,"given":"Maryam","family":"Pourhassan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,3,27]]},"reference":[{"key":"1604_CR1","doi-asserted-by":"publisher","first-page":"583","DOI":"10.1111\/ejh.12776","volume":"97","author":"M Levi","year":"2016","unstructured":"Levi M, Rosselli M, Simonetti M, Brignoli O, Cancian M, Masotti A, et al. 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All methods were performed in accordance with the relevant guidelines and regulations. In addition, written informed consent was waived due to retrospective data collection.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethical approval"}}]}}